col(1)                                                     col(1)



     NAME
          col - filter reverse line-feeds

     SYNOPSIS
          col [-b] [-f] [-p] [-x]

     DESCRIPTION
          col reads from the standard input and writes onto the
          standard output.  It performs the line overlays implied by
          reverse line feeds (ASCII code ESC-7), and by forward and
          reverse half-line-feeds (ESC-9 and ESC-8).  col is
          particularly useful for filtering multicolumn output made
          with the .rt command of nroff and output resulting from use
          of the tbl(1) preprocessor.

          If the -b flag option is given, col assumes that the output
          device in use is not capable of backspacing.  In this case,
          if two or more characters are to appear in the same place,
          only the last one read will be output.

          Although col accepts half-line motions in its input, it
          normally does not emit them on output.  Instead, text that
          would appear between lines is moved to the next lower full-
          line boundary.  This treatment can be suppressed by the -f
          (fine) flag option; in this case, the output from col may
          contain forward half-line-feeds (ESC-9), but will still
          never contain either kind of reverse line motion.

          Unless the -x flag option is given, col will convert white
          space to tabs on output wherever possible to shorten
          printing time.

          The ASCII control characters SO (\016) and SI (\017) are
          assumed by col to start and end text in an alternate
          character set.  The character set to which each input
          character belongs is remembered, and on output SI and SO
          characters are generated as appropriate to ensure that each
          character is printed in the correct character set.

          On input, the only control characters accepted are SPACE,
          BACKSPACE, TAB, RETURN, NEWLINE, SI, SO, VT (\013), and ESC
          followed by 7, 8, or 9.  The VT character is an alternate
          form of full reverse line-feed, included for compatibility
          with some earlier programs of this type.  All other non-
          printing characters are ignored.

          Normally, col will ignore any unknown escape sequences found
          in its input; the -p flag option may be used to cause col to
          generate these sequences as regular characters, subject to
          overprinting from reverse line motions.  The use of this
          flag option is highly discouraged unless the user is fully
          aware of the textual position of the escape sequences.



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     col(1)                                                     col(1)



     EXAMPLE
               nroff -mm filea | col

          pipes multicolumn nroff output through the col filter to
          enable proper creation of columns.

     FILES
          /usr/bin/col

     SEE ALSO
          nroff(1), tbl(1).

     NOTES
          The input format accepted by col matches the output produced
          by nroff with either the -T37 or -Tlp flag options.  Use
          -T37 (and the -f flag option of col) if the ultimate
          disposition of the output of col will be a device that can
          interpret half-line motions, and -Tlp otherwise.

     BUGS
          Cannot back up more than 128 lines.
          Allows at most 800 characters, including backspaces, on a
          line.
          Local vertical motions that would result in backing up over
          the first line of the document are ignored.  As a result,
          the first line must not have any superscripts.





























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